X-ray Raman scattering in colloidal and polycrystalline graphite

Abstract

Raman scattering was measured in colloidal and polycrystalline graphite for a scattering angle 45°, using X-ray CrKβ radiation and a mosaic graphite analysing crystal spectrometer without collimators. The use of such a spectrometer was necessary because of the weakness of the Raman effect.For the colloidal graphite, an energy shift of ΔE = 288.3 ± 0.6 eV from the primary line was observed. For the polycrystalline graphite, the above shift was ΔE = 284.9 ± 0.5 eV. These shifts can be ascribed to the transition of the 1s electrons onto and above the Fermi level, constituting the so-called Raman band.In the polycrystalline graphite, an additional anomaly was observed in the spectrum, beyond the Raman band towards the low energies, i.e., in 311 eV. This fine structure is a verification of the Weaire–Thorp concept about the difference in the spectra, due to the short-range and long-range order.